My 280 currently has a five speed, but I have no idea if it's the original transmission. Heck, I don't even know if the car originally came with a 4 speed or a 5 speed. So...

How do I tell if my 280 left the factory as a four speed or five speed?

Beyond that, if it did leave the factory as a 5-speed, is there any way to tell if the transmission in it is the original one?

My first ''77 5-speed had a badge on the rear hatch.

The 5 speed was introduced as an option in 1977 as I understand it. Not sure what year your 280 is.

I don't think you can tell if the transmission is original or not. If the interface between the engine and transmission looks factory fresh, you might think that it's never been removed. That would be a sign anyway. Otherwise, the numbers on the transmission are apparently irrelevant to anything.

Did not know that. I knew the numbers were useless for determining 4 or 5 speed, but didn't know they had date information. Thanks for the insight. Wish I had looked at mine before I installed it...

Went out and looked at my ZX 5 speed (came out of a 1981 ZX but has 1980 ratios), easier to see than I thought, and it has 7409303. It's definitely a ZX body, with the speedo hold down bolt at 6 o'clock.

Looked at the various transmissions I've collected (kind of embarrassing)

"1980" 280ZX (above) - 7409303

Original (as far as I can tell) 1976 280Z 4 speed - 7106146

1978 280Z 5 speed - 7128997

1983 280ZX (speedo bolt down) - 7X64820

Blown up ZX 5 speed year unknown - 7X64845

Edit - those really are Xs in the strings above, not illegible numbers.

Just observations. So I'm back to not seeing any information in these numbers. Maybe Nissan stockpiled a boatload of bellhousings and the numbers show when they were made.

Edited January 27, 201213 yr by Zed Head

My 280 is a 77. Build month of April, 1977.

What I'm asking is... Is there any way to tell if it was originally a five speed, or did a previous owner pull a four speed and stick in a five speed in it's place?

I don't have the "Five Speed" insignia on the hatch, but I do have one in a box of trim parts that the previous owner says he took off when he painted the car. Doesn't guarantee that it came like that originally, but certainly supports the theory.

The previous owner did a whole bunch of work to the car and there's very little left that's "factory fresh". I know the engine and transmissions have been out, and painted. I know that the previous owner that I bought it from did not replace the engine or tranny, but I have no idea about owners before him.

I know that I'm missing the ID plate that's supposed to be inside the engine compartment.

The transmission type isn't built into the VIN in any way, is it?

Looked at the various transmissions I've collected (kind of embarrassing)

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removed long list for brevity

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Haha. You need to cut down a little!

There is a site that shows the unique case indicators that show if its a 77-78 5sp, or one of the two zx 5 speeds. dual or one-sided muffler hanger castings back at the tail, and long or short ears where the shifter pin goes through. Dual muffler bracket w/ short shifter ears is the 77-78 5sp I believe. Single sided muffler hangers are all zx, long ears make it the 82-83 5sp. (T5 not included in this discussion).

This does not help you understand if your car came with a factory 5, just clarifies the origin of the trans you have in there now. Hope this helps

There is a site that shows the unique case indicators that show if its a 77-78 5sp, or one of the two zx 5 speeds. dual or one-sided muffler hanger castings back at the tail, and long or short ears where the shifter pin goes through.

I have seen that on the bottom of this page: http://www.geocities.com/inlinestroker/ratio.html

You could look for the holes in the hatch, from the inside, where the "Five Speed" (or "5 Speed", thought it was the numeral?) insignia would have been mounted. At least you'd know it came with the insignia.

You could look for the holes in the hatch, from the inside, where the "Five Speed" (or "5 Speed", thought it was the numeral?) insignia would have been mounted. At least you'd know it came with the insignia.

They are adhesive mounted.....

Edited January 27, 201213 yr by sblake01

Thanks for the additional info.

So it seems that I'm relegated to circumstantial evidence...

• I've got a five speed in the car.
  
• A 5-Speed insignia came with (but not attached to) the car.
  
• I checked the serial number on my bell housing and the numbers are shallow and filled with paint, but there's no mistake that the first two numbers are "74" which, if the number stampings really do mean something, puts it at a mfg date of April 77 and that is the same as the build date of the car.
  

Next time I have the car out of the garage, I'll check visually to see if I can verify that it is an early "wide ratio".